You've got me here, @Mila W.
The possible reason why you're unable to upgrade your QuickBooks 2009 is due to system requirements. Also, the unsupported version can cause issues while using online functions like migration to QBO. (Note that Intuit doesn't offer a download for an unsupported version like an update for the latest release).
So, what we're going to do is to open your file to different versions. This way, you can open it to QuickBooks 2018. We'll start to open and upgrade your file to the 2012 version, then 2015, and 2018. I'll share the link on where you can download these versions.
For more information, see Step 3 through this article: Upgrade Your Company Files.
Once everything is done, you can now migrate your QBDT file to QBO. To learn more about it as well the limitations during the migration, check out these articles for your references:
Reach out to me if there's anything else you need. I'll be here to keep helping. Take good care.
Hello there, Mila W,
If you have purchased support with your QuickBooks Desktop 2009, we can help convert the file for you. Simply chat our live support team through this link: https://help.quickbooks.intuit.com/en/contact.
You can also contact us inside your company file. Let me show you how:
Check our support hours to learn when to contact us at a time convenient to you.
If you haven't purchased a support, you can visit this store: QuickBooks Desktop app. And, look for an app to help convert the file.
Let me know if you need additional information, and I'm always right here to help migrate your data.